1. Field of the Invention
The present invention relates to an endoscope apparatus and specifically relates to an endoscope apparatus capable of determining a focusing state for an image.
2. Description of the Related Art
Conventionally, endoscope apparatuses have widely been used in medical and industrial fields. For example, in the medical field, a surgeon inserts an insertion portion of an endoscope into a body cavity to display an object image picked up by an image pickup device provided at a distal end of the insertion portion on a monitor, whereby the surgeon can observe a site of an object to make a diagnosis. In recent years, endoscope apparatuses having what is called an autofocusing function have been put into practical use. For example, there are endoscope apparatuses in which a focal position can be set to either a near point position or a far point position and the setting can be switched between the positions.
In general, the autofocusing function of an endoscopic image is performed based on a focusing evaluation obtained by comparison of levels of contour enhancement signals. For example, as disclosed in Japanese Patent Application Laid-Open Publication No. 2004-258360, endoscope apparatuses that perform a focusing evaluation for an image using contour enhancement processing have been proposed.